Well, I didn't consider MWF, so I can't compare, but we are using FIAR and I could not be more excited! I also have a young Ker. He turned 5 in June. His 4yo siblings will be tagging along. I bought volumes 1-3 and chose ~18 books from them (some from each) that looked like they'd fit our interests. I plan to use some of the books I skipped next year for 1st grade. I'm adding phonics, handwriting, and math, and think it'll be a great year!